External transpedicular spine fixation in severe spondylodiscitis - salvage procedure

Abstract

Specific and non-specific infections of the spine are rare. Due to their potential for severe instabilities, deformities and the impairment of neurological structures, the treatment is often prolonged and needs an interdisciplinary management. The clinical presentation is uncharacteristic, therefore diagnosis is often delayed. There are no prospective randomized studies for therapy recommendation. The surgical concept includes eradication of the infection and the reliable stabilization of involved segments. This concept is successful in most cases of endogenous vertebral osteomyelitis. The therapy of the exogenous spine infections after macro and micro surgery is more difficult, due to the critical wound situation and the involvement of the posterior parts of the spine. In these cases, infection-associated instability of the anterior part is complicated by critical posterior wound conditions. We present three cases of severe exogenous vertebral infections, where temporary external transpedicular spine fixation was used for salvage procedure, till soft tissue conditions have permitted a definitive internal stabilization.

Keywords: exogenous spine infection; exogenous vertebral osteomyelitis; external spine fixation; spondylodiscitis.

Figure 1. Left: Posterior bisegmental stabilization and anterior reconstruction after burst fracture of L1. Right: Septic implant loosening: Cage displacement and cut out of the distal pedicle screws after one year.

Figure 2. Temporary external posterior long segment stabilization (Hoffmann II external fixator, 5 mm pins). Surgical debridement of the anterior column and antibiotic chain spacer implantation.

Figure 3. Left: Procedural change. Internal posterior stabilization Th11/12 – L2/3 (Longitude/Medtronic; 6.5 mm pedicle screws). The antibiotic chains were left in situ. Because of the good bone quality, a pedicle screw augmentation was not necessary. Right: Removal of the antibiotic chains after further 4 weeks. Due to a progressive osseous bridging, there was no need for an anterior stabilization.

Figure 4. Left: Adjacent segment instability after L2/3 PLIF. Right: The sagittal and transverse MR Imaging reveals the extended infection spread in the trunk- and psoas muscles. Additionally, there is increasing signal intensity in the adjacent disc space L1/2, that indicates infection.

Figure 5. Temporary external posterior stabilization Th10/11 – L4/5 (Hoffmann II external fixator, 5 mm pins). The intersomatic antibiotic chain interposition after retroperitoneal surgical debridement provides high local antibiotic concentrations.

Figure 6. External spine stabilization using Hoffman II external fixator. The vacuum assisted closure therapy is necessary for soft tissue conditioning.

Figure 7. Posterior long segment internal stabilization Th10/11/12 – L4/5 using cement-augmented pedicle screws (Longitude, Medtronic). Anterior internal fixation as well as palacos spacer implantation between L1 and 2 (Antares, Medtronic).

Figure 8. L1 compression fracture in severe osteoporosis led to kyphosis and spinal cord compression. Long segment posterior stabilization and multilevel decompression.

Figure 9. The sagittal CT image reveals the extent of the posterior instability.

Figure 10. Left: Local findings. Right: Intraoperative findings.

Figure 11. Figure 11. Left: Complete implant removal, radically surgical debridement and external spine fixation with vacuum wound closure (Hoffmann II external fixator, 5.0 mm Pins). Right: X-ray Image of the thoracolumbar spine. External posterior stabilization.

Figure 12. Follow-up after VAC therapy

Figure 13. Wound closure

Figure 14. X-ray image of the final internal posterior stabilization (Longitude, Medtronic; cement-augmented pedicle screws, 7.5 mm)